i don’t want to offend anyone, but some open source/privacy enthusiasts dislike google, but why?? google has made chromium, android, etc and most of the things they do are open source, and not only that, they also support creative commons media or public domain. i know the privacy concernes they may have, but they would never do anything bad to you. i love google personally because of their commitment to open source software.
They collect much more than that, such as location data, and huge amounts of info gleaned from email and photos.
One of the main priorities of the google maps cars is to also map wireless networks, so when your phone locates a wireless network, Google also knows your location (and the location of those connected to said network).
Note: This is also done passively by Android phones.